1. Field of the Invention
The invention is concerned with a unitary seal adapted for use in an articulated joint and formed of two distinct materials having different properties, said materials being directly bonded together without the use of an adhesive between them.
2. Prior Art
A standard track pin seal normally comprises a one-piece elastomeric sealing member which is reinforced by a backing member to provide support therefor. Composite seals of this type present a number of problems. First, the seals are not of unitary construction and the parts thereof can be dislodged relative to one another. This problem is particularly apparent when the seal is employed in heavy-duty construction equipment.
The adhesive securance of the backing member to the sealing member does not adequately solve such a problem because the adhesive used may not exhibit sufficient cohesive strength, formation of the composite seal requires careful positioning of the parts together to avoid misalignment, and/or the adhesive might not be completely uniformly spread between the two parts of the seal whereby leakage could occur in the non-adhered portion of the seal.
The present invention provides a unitary seal wherein support and sealing sections thereof are directly bonded together without the use of an adhesive. This provides a unitary seal of great toughness which can be used in rough environments, such as in an articulated joint of an endless track assembly of a track-type vehicle.